PLATE XXII 



FIG. i. Lineus rubcsccns Coe. Transverse section of head in front of brain, 

 showing distribution of cutis glands (cugl], the highly developed cephalic glands 

 ( -/), and the duct (a) leading forward beneath the rhynchodaeum (r/i). This 

 duct is probably the common efferent canal for the secretions of the more pos- 

 terior cephalic glands ; cf, cephalic furrow ; bl, blood lacuna ; cm, circular muscles. 

 XSo. 



FIG. 2. Carinella frenata Coe. Portion of transverse section of head, show- 

 ing the deep ciliated pit (cf) from which a ciliated sensory canal (cc) leads inward 

 to the brain region, where it becomes surrounded with sensory nerves (sn) from 

 the dorsal side of brain to form a highly specialized sense organ ; *, integument; 

 Jt, laver of fibrous connective tissue surrounding brain ; cm, circular muscles ; 

 br, fibrous core of brain, surrounded except internally by a thick layer of nerve 

 cells ; bm, basement membrane. X 60- 



FIG. 3. Carinella frenata. Portion of transverse section of body through 

 lateral sense organ; /, integument, sharply contrasted with the layer of special- 

 ized sensory cells lining the sensory pit; /, lateral nerve; Iv, lateral blood 

 vessel ; sep, epithelium of stomach ; icm and ocm, inner and outer circular mus- 

 cular layers ; Im, longitudinal muscles. X 6- 



FIG. 4. Tctrastemma bilineatum Coe. Portion of transverse section of body. 

 The two pigment bands (pig] which give the body its characteristic markings 

 are situated in the midst of the longitudinal muscles (/*), on either side of the 

 proboscis sheath (re) ; ine, intestinal epithelium ; other reference letters as in 



fig- 2. 



(230) 



